Roller bit



July 20, 1937. A. c. CATLAND 2,087,501

ROLLER BIT Filed Jan. 14; 193e 2 sheds-sheet 1 July 2o, 1937.

A. C. CATLAND ROLLER B IT 2 Sheets-Sheet 2 Filed Jan. 14, 1936 Patented July y 2o, 1937 UNITED STATES ROLLER BIT Alfred C. Catland, Alhambra, Calif., assignor to 'Globe Oil Tools Company, Los Nietos, Calif.,

a corporation of California Application January ,14, 1936, Serial No. 59,075

15 Claims.

rlhis invention relates to a well drilling tool and relates more particularly to a roller bit for use l in the rotary method of well drilling. A general object of this invention is to provide a practical e'ective and long wearing roller rock bit.

Another object of this invention is to provide a roller bit in which the several roller cutters are carried by a. small, compact and strong removable carrier. l0

a roller bit in which the screws attaching the cutter carrier to the bit body are not subjected to any stresses resulting from the drilling operation so that these screws and the body parts in which they thread may be small, to promote the drilling efficiency of the bit.

Another object of this invention is to provide a roller bit of the character mentioned in which the screws securing the cutter carrier to the bit body have their heads in the carrier assembly and thread outwardly into openings in the legs of the body whereby said legs may be relatively light or small to promote the general efficiency of the' bit. Another object of this invention is to provide a roller bit embodying improved bearing bushings on the carrier for rotatably supporting the cutters, which bushings may be treated or hardened to be lo-ng wearing and operate to protect the carrier against the action of the rotating cutters g so that the carrier may be formed of tough,

strong material.

Another object of this invention is to provide a roller bit of the character mentioned in which the bushings rotatably supporting the cutters di4 rectly transmit to the body of the bit the stresses, resulting from the active contact of the cutters with the formation, thereby relieving the carrier and the carrier securing screws of these stresses.

Another object of this invention is to provide a roller bit of the character mentioned in which the bearing bushings have integral thrust washers or anges receiving the end thrusts from the cutters.

A further object' of this invention is to provide a roller bit that is eflicient in operation and that embodies a minimum number of simple, sturdy parts.

'I'he various objects and features 'of my invention will be fully understood from the following detailed description of a typical preferred form and application of my invention, throughout which description .reference is made to the accompanying drawings, in which:

Fig` 1 is a side elevation of the bit provided by this invention with a portion broken awayto illust-rate the rotatable mounting of one of the Another object of this invention is to providey outer cutters. Fig. 2 is an enlarged longitudinal detailed sectional view of the bit body and the assembly of the carrier and cutters. Fig. 3 is a bottom elevation of the bit. Fig. 4 is a bottom elevation of the bit body with the cutter carrier removed. Fig. 5 is a fragmentary vertical detailed sectional view similar to Fig. l-2 illustrating the manner o f assembling the carrier in the body. Fig. 6 is a side elevation of a bushing for carrying one set of inner cutters. Fig. 7 is an end view of the bushing illustrated in Fig. 6. Fig 8 is a side elevation of a bushing for carrying an outer cutter. Fig. 9 is an end elevation of the bushing illustrated in Fig. 8. Fig. 10 is a top Orp-lan view of the cutter carrier. Fig. 11 is aside elevation of the cutter carrier and Fig. 12 is a transverse detailed sectional view taken as indicated by line I2-I2 on Fig. 2.

The well bit provided by this invention includes,

generally, a shank I0, a bit head or body I-I re- H movably attached to the shank I0, a spider or carrier I2 detachably secured .to the body II, outer roller cutters I3 and sets of inner cutters 52 and 53 supported by the carrier I2.

The shank I0 is adapted to' be connected with the lower end of a well drilling string and is pro# vided to carry the bit body II.. In practice the shank III may be a simple elongate :member provided at its upper end with means for facilitating its connection with the drilling string. In the particular case illustrated in the drawings the upper end of the shank I0 is provided with a tapered screw threaded pin I5. The lower end portionA I6 of the shank I0 is shaped and proportioned to carry the body II being cylindrical in shape and being reduced in diameter. An annular downwardly facing shoulder I 'I occurs at the upper end of the reduced shank portion I6. A central longitudinal fluid passage I8 extends through the shank I0 from one end to theother. A fluid discharge device or nozzle I9 is provided at the lower end of the passage I8. The nozzle I9 may t a tapered socket 20 at the lower end of the passage I8. A plurality of 'downwardly and outwardly inclined discharge ports 2| is provided in the nozzle I9.

The bit head or body II is detachably secured to the shank I0 `to extend from its lower end and 2 r shank I by an effective-[bayonet type joint.' 'Ihe body II is socketed or tubular having a central longitudinal opening y22 receiving the reduced end portion I3 of the shank I3. Diametrically opposite bayonet slots or grooves are provided in the wall' of the body II .to receive lugs 23 on the 'A shank/portion I6. Each of these bayonet grooves includes a substantially vertical portion 24 exvv tending downwardly from the upper end of the body II and a substantially horizontal portionv II) so that the lugs 23 are received in the inner` ends of the transverse groove portions 25. KeysY 21 are then inserted in the vertical portions 24 of the bayonet grooves to lock the lugs 23 in place.

The parts/are preferably related so that the keysv 21 are entered behind the lugs 23 relative to the direction of rotation of the bit.` Screws 28 may be threaded inl openings'in the shankl- I0 at the upper ends of the keys 21 to prevent the upward displacement ofthe keys. With the bit body II Vsecured to the shank I0 by the bayonet slot connection just described 4the upper end of the body may bearupwardly on the shank shoulder I1.

The lower projecting portion of the body II which is provided to receivel the carrier I2 is provided with two sets of diametrically opposite legs 23 and 30. The legs 29 and 3II are spaced approximately `90 apart and project downwardly and somewhat outwardly as illustrated in Figs. 1, 2vand 5 of the drawings. 'I'he opposite sides ofthe legs 29 and 30 may converge downwardly so that the legs are of relatively small dimensions at their lower ends. The legs 2 9y have inner sur' faces 3I inclined downwardly and outwardly relative to the longitudinal axes of the bit. Downwardly facing shoulders 32 are providedon Y the surfaces 3| adjacent their upper ends. lSubstantially vertical inner surfaces 33 are provided r on the legs 30. Each surface 33 is provided with a downwardly facing shoulder 34 spaced a conslderable distance above its lower end.

The carrier I2 is a spider-like part assembled within vthe series of legs 29 and 30 to carry the cutters I3 and the cutters 52 and 53. The carrier I2 is preferably integral and includes a main `bridge or web 33. 'I'he web 33 is disposed transversely or horizontally and has its principal axis (in the plane of the vertical axes of the diametricallyopposite legs 23. The web 35 is substantially wedge shaped in vertical cross section hav- .ing downwardly o'r inwardly inclined sides.

Downwardly and outwardly inclined annular thrust surfaces or bearing sln'faces 33 are provided at ,the opposite ends of the web 33. The surfaces 33 lare spaced from and substantially parallel to the inner surfaces 3I of the legs 29. In accordance with the invention tapered screw threaded pins'31y project upwardly and outwardly from the bearing surfaces 33. The longitudinal The partsarevproportioned so that the outerk axes of the pins 31 aresubstantially normal to the surfaces 3I and 33.. Central openings or sockets enter the pins A31 from their outer ends.

ends of the pins 31 are spaced Ls'ome distance.l from "the inner sides 3l of the legs 29. Thecutter carrIer .I2includes integral pins 33 proiectin'gfrom The bit body II may be I the bit body II.

the opposite sides of its web 33 toward the legs 33. The pins 39 are threaded and suitably tapered. In the preferred construction the pins 39 are inclined downwardly and outwardly having their longitudinal axes lying in `the verticalplane of the legs 30. As the carrier I2 merely forms a mounting for the cutters I3 and I4 and does not directly rotatably support the cutters it maybe formed of a tough steel to be capable of dependably withstanding the stresses and forces to which it may be subjected.

The outer cutters I3 are providedto act on the outer portion of the well bore and are positioned between the inner sides of the legs 23 and the surfaces 36 of the carrier I2. The outer cutters I3 are substantially frusto-conical roller cutters having suitable peripheral cutting teeth 40. The outer ends of the cutting teeth 4II are bevelled away as at 4I. Each outer cutter I3 has a central longitudinal opening 42.

,The invention provides novel and particularly effective bearing bushings 43 lfor rotatably supporting the outer cutters I3. The bushings 43 are threaded on the pins 31 having sockets 44 receiving the threaded pins.v The bushings 43 are carburized or otherwise hardened to be very long wearing. The innerI ends of the wear taking bushings 43 may bear on raised portions of the surfaces 33. Each bushing 43 is provided with a cylindrical external bearing surface which rotatably carries an outer cutter I3. It may be -preferred to rotatably support the cutters I3 on the bushings 43 through suitable roller bearings 43.l The inner ends of the cutters I3 may have thrust transmitting cooperation with the annular surfaces 33 ofthe carrier I2. In accordance with the outer ends with integral thrust washers or thrust invention the. bushings 43 are provided at their flanges 46 to receive the principal end thrusts from the cutters I3. Theouter sides of the flanges 46 which also form theouter ends of the bushings 43 bear outwardly against the inclined inner surfaces 3i of the legs 2 9 for the direct transmission of the drilling forces and stresses between the body legs and the cutter supporting bushings. An upwardly facing shoulder 41 is provided on the outer side of each flange 43 to cooperate with the shoulder 32 on the inner side of a leg 29. 'Ihe cooperation of the shoulders 41 and 32 locks the bushings 43 against unthreading from the pins 31 and provides for the eective transmission of the drilling pressures and forces between the cutter supporting bushings 43 and 'Ihe flanges 43 of the bushings 43 may extend downwardly beyond the lower ends of the body legs 39 and their lower ends may be suitably bevelled.

nous or screws u connect the pins a1 of the i .adapted to bear outwardly against the bushings*I 43 at the outer ends ofthe pins 31. The screws 43 serve to connect the carrier pins 31 with the legs.29 but are not subjected to the drilling forces 'and vstresses as these forces and. stresses are directly transmitted by the cooperating surfaces of the bushings 43 and the legs 29. The-outer .cutters-ju rotatably on the busmdgs' 43 as just described project downwardlybeyond the lower'ends of the legs 29 and rotate about downwardly and inwardly inclined axes.

The inner cutters 52 and 53 are provided to act on the major inner portion of the well bore and are provided in series or sets positioned between the body legs 30 and the web 35 of the carrier I2. Each set of inner cutters comprises two roller cutters 52 which may be of the same diameter and a larger roller cutter 53 forming the outermost cutter of the set. The cutters 52 and 53 are preferably cylindrical and are provided with suitable cutting teeth. The bit includues simple, ef-

fective bearing bushings 54 for rotatably supm r porting the sets of inner cutters. vThe bushings 54 have central longitudinal openings 55 whose inner portions are threaded to receive the pins 39 of the carrier l2. An inwardly facing shoulder 56 is provided on the wall of each bushing opening 55. When the bushings 54 are properly threaded on the carrier pins 39 the inner ends of the bushings may bear on the downwardly convergent sides of the carrier web 35. The bushings 54 have cylindrical external bearing surfaces for rotatably carrying the cutters 52 and 53. The cutters 52 and 53 may be rotatably supported on the bushings v54 through suitable roller bearings 51. The inner ends of the innermost cutters 52 may bear on the sides of the carrier web 35.

The invention providesintegral thrust washers or flanges V58 on the bushings -54 to receive the principal operating thrusts from the inner cutters; The inner surfaces of the anges 58 are normal to the longitudinal axes of the bushings 54 while the outer surfaces of the flanges 58 bear on the inner surfaces 33 of the legs 30. Upwardly facing shoulders 59 are provided'on the outer sides of the flanges 58 to cooperate with the shoulders 34 on the legs 30. The cooperation of the shoulders "59 with the shoulders 34 locks the bushings 54 against unthreading from the pins 39 and dependably transmits the drilling forces directly between the body I I and the bushings 54; The lower ends of the flanges 58 which may extend beyond the lower ends of the legs 30 may be suitably tapered or bevelled.

Screws 60 are provided to connect the pins 39 and their bushings 54 with the adjacent body legs 30. The screws 60 are passed outwardly through the openings 55 in the bushings 54 and are threaded into openings 6I in the legs 30. The heads of the screws 69 are adapted to bear outwardly against the shoulders 56 so that the screws form effective connections between the legs 30 and the adjacent bushings 54. Wrench sockets 62 are provided in the outer ends of the screws 60 to facilitate the threading of the screws. The inner cutters 52 and 53 rotatably supported as just described rotate about downwardly and outwardly inclined axes to act on or form a central conical mound of earth formation which effectively centers the bit. The cutters 53 being larger in diameter than the cutters 52 form a shoulder or step in this conical surface of the formation and project downwardly to operate in advance ofthe lower ends of the body legs 30 and the bushing flanges 58. The ports 2| of the nozzle I9 are located and formed todirect streams of circulation fluid downwardly against the cutters I3, 52 and 53.

In assembling the bit the screws 48 are arranged in the bushings 43 and the screws 60 are arranged in the bushings 54. The cuttersl3' with their bearings are then assembled on thc bushings 43 and the cutters 52 and 53 with their bearings are assembled on the bushings 54. The bushings 43 and 54 are then threaded on their respective pins 31 and 39. The screws 48 and 60 are retracted or arranged so that they do not project from the ends of the bushings 43 and 54 to permit the carrier to be inserted between the legs ofthe body II. Fig. 5 of the drawings illustrates the assembly of the carrier I2 and its cutters being entered in the bit body. Due to the diiculty that may be encountered in insuring the proper contact of the surfaces 41 with the surfaces 32 and the contact of thev shoulders 59 with the shoulder 34 it may be preferred to cut or form the shoulders 41 and 59 during the assembling of the tool. When the assembly of the carrier I2 and its cutters has be'en arranged so that the shoulders 41 and 59 are in proper contact with the body shoulders 32 and 34 wrenches may be entered through the openings and 6I to engage in the wrench sockets 63 and 62 to` thread the screws 48 and into the legs. These wrenches may be such that they expand or grip the screws 48 and 60 so that the screws may be lreadily moved outwardly and threaded into the openings in the body lugs. The threading or the screws 48 and 60 into the openings 58 and 6I nally secures the removable carrier I2y to the bit body II. The tool is then in condition for operation.

In the operation of the roller bit the several roller cutters I3, 52 and 53 simultaneously have rolling or cutting engagement with the formation at the bottom of the well bore as the bit is rotated. 'I-he outer cutters I3 cut the wellbore to gauge and act on the outer portion of the bottom Wall of the well. The inner cutters 52 and 53 are rotatable about downwardly and outwardly inclined axes so that they form and engage a conical mound of the earth formation which engagement operates to center and stabilize the bit. It will be noted that the carrier I2 is not subjected to the wearing action of the rotating cutters and is not subjected to the heavy stresses during the drilling operation. The cutter supporting bushings 43 and 54 have extensive surface engagement with the inner sides of the legs 29 and 30 and have shouldered engagement with the legs for the direct transmission of the drilling forces and stresses. This cooperation of the cutter supporting bushings with the body legs relieves the carrier I2 of the transmission of the principal drilling stresses.

The engagement of the shoulders on the cutter and 34 also locks the bushings against unthreadl ing from the carrier pins 31 and 39 to positively prevent loosening of the assembly.

Having described only a typical preferred form and application of my invention, I do not Wish to be limited or restrictedto the specific details herein set forth, but wish to reserve to myself any variations or modifications that may appear to those skilled in the vart or fall within the scope of the following claims.

l Having described my invention, I claim:

1. In a roller bit, a body, a detachable carrier, a bearing part threaded on the carrier, a cutter rotatable on the bearing part, and shoulders on the body and bearing part cooperating to prevent unthreading of the bearing part and to transmit forces between the body and bearing part.

2. In a roller bit, a body, acarrier removably secured tothe bodyand having a pin, a bushing threaded on the pin, a cutter rotatable on 4. A well bit comprising a body having a leg,

a removable carrier having a pin projecting toward the leg, a downwardly facing shoulder on the inner side of the leg, a bushing threaded on the pin and having a thrust ange 'bearing outwardly against the leg, an upwardly facing shoulder' on the flange cooperating with the first named shoulder, and a cutter rotatable on the bushing and bearing outwardly against. the

f flange.

5. A well bit comprising a body, a leg on the body having a shoulder on its innerside, a carrier having a pin projecting toward the leg, a bushing threaded on the pin and having force transmitting cooperation with the inner side of the leg, a cutter rotatable on the bushing, and a shoulder on the bushing cooperating with the rst named shoulder to transmit thrust and to prevent unthreading of the bushing.

6. A well bit comprising a body, a leg on the body having a shoulder on its inner side, a carrier having a pin projecting toward the leg, a bushing threaded on the pin and havingvforce transmitting cooperation with the inner side of the leg, a flange onl the bushing, Ya rotatable cutter on the bushing bearing outwardly against the ange, and a shoulder on the flange cooperating with the first named shoulder for the transmission of thrusts and for preventing unthreading of the bushing. l i

7. In a roller bit, a body, a carrier removably secured to the body and having a pin, a bushing threaded on the pin, a cutter rotatable on the bushing, cooperating shoulders on the body and bushing transmitting thrusts and preventing kunthreading of the bushing, and a screw extending outwardly from the bushing and threaded in an vopening in the leg to secure the vcarrier to the body.

8. In a well bit, a body having' a leg, a removable carrier having a pin projecting toward the leg, a bushing secured to the pin, a cutter rotatable on thebushing, and a screw extending from the bushing'and threaded in an opening in the leg to securethe carrier to the leg.

9. In a Well bit, a body having a leg, a -remov'- able carrier having a pin projecting toward the leg, a tubular bushing threaded on the pin, a cutter rotatable on the bushing, and a screw extending from the bushing and threaded in an opening in the leg to secure the carrier to the leg. I

10. In a well bit, a body having a leg, a removable carrier having a pin projecting toward the leg, a tubular bushing threaded on the pin and having an internal shoulder, aY cutter rotatable on the bushing, and a. headed screw arranged in the bushing to have its head bear on said shoulder and threaded in an opening in the leg to connect the carrier with the leg.

11. In a well bit, a body having a leg, a4 removable carrier having a pin projecting toward the leg, -a tubular bushing threaded on the pin and having an internal shoulder, a. cutter rotatable on the bushing, cooperating shoulders o'nk the leg and bushing preventing unthreading of the bushing, and a screw passed outwardly in the bushing and threaded in an opening in the leg to connect the carrier with a leg.

12. In a well bit, a carrier "comprising a web,

` pins projecting from the opposite ends of the web, pins projecting from the opposite sides of the web, bushings threaded o'n the pins, and

` cutters rotatable on the bushings.

13. In a Well bit, a carrier comprising a web,

pins projecting from the opposite ends of the web, pins projecting from the opposite sides of the web, bushings threaded on the pins, flanges on the bushings, and cutters rotatable on the bushings between the flanges and the web.

14. A well bit comprising, a body having spaced legs, a carrier inserted between the legs, pins on the carrier projecting toward the legs, bushings threaded on the pins, flanges on the bush'- ings bearing on the legs and cooperating with the legs to prevent unthreading of the -bushings, cutters rotatable on the bushings, and

screws connecting the bushings with the legsr to attach the carrier to the body.

15. In a well bit, a body having a leg, a removable carrier having a. pin projecting toward the leg, a tubular bushing threaded on the pin and having an internal shoulder, a. cutter rotatable on the bushing, and a headed `screw arranged'in thebushing to have its head bear on said shoul der and threaded in an opening. in the leg to connect the carrier with the leg, there being an accessible wrench socket in the outer end of the screw.

ALFRED C. CATLAND. 

